Titanium catalysts comprising a titanium compound and an organoaluminum compound, and vanadium catalysts comprising a vanadium compound and an organoaluminum compound, are known as catalysts used in production of olefin polymers, such as ethylene polymers and ethylene/α-olefin copolymers.
Ziegler catalysts comprising a metallocene compound, such as zirconocene, and an organoaluminum-oxy compound (aluminoxane) are known as catalysts enabling production of olefin polymers with high polymerization activity.
Recently, novel olefin polymerization catalysts comprising a transition metal compound having a salicylaldimine ligand are described in JP-A-11 (1999)/315109 to exhibit high olefin polymerization activity. Further, JP-A-2001/2731 describes a novel low-molecular-weight ethylene polymer having a double bond in one terminal position, a modified product thereof obtained by modifying the double bond in one terminal position, and uses of these polymer and modified product, such as a toner release agent, a pigment dispersant and a lubricant for vinyl chloride resins.
To exert higher performances in such uses and to find other applications, these polymers are required to have an increased content of the double bond in one terminal position of the polymer chain (such a double bond will be sometimes referred to as “one-terminal double bond” hereinafter).